This invention relates to latches that are flush or near flush when mounted in a door or frame. Typically, the latch handle is contained with this low profile while not in use, but may be extended in some way to provide access to an operator. Once extended, the handle may be operated to open the door.
One example of such a generally flush mounted latch assembly is U.S. Pat. No. 5,450,735, issued to Takanobu Esaki, et al. of Tokyo, Japan on Sep. 19, 1995. Esaki discloses a pull-out-and-rotate type latch assembly. When locked, the latch handle lies nearly flush with the surrounding housing and door. When unlocked, the handle may be pivoted to an extended position and turned thereby turning a latching plate at the end of a spindle, allowing the door to be opened. Another example of a flush type latch assembly is U.S. Pat. No. 5,457,971, issued to Kenichi Yamada of Tokyo, Japan on Oct. 17, 1995. Yamada discloses a push-button spring-loaded rotary type latch assembly in which a torsion spring urges the handle into an extended position when a push-button is depressed.
In both Esaki and Yamada, the key cylinder is mounted in the handle and the shaft and latching plate can only rotate. Since the key cylinder is mounted in the handle, the length of the handle is dictated in part by how many fingers must fit between the key cylinder and the handle's pivot. Since the latching plate in each does not move axially but only rotates, it does not additionally cinch the door to the frame upon closing. Also, a separate push button mechanism is utilized to release the handle.
What is needed is a push-button type flush mounted latch assembly wherein the push button mechanism is greatly simplified. Additionally, what is needed is such a latch in which the key cylinder may work just as well if mounted in the housing rather than the handle. What is further needed is a latch assembly that causes the latching pawl to both rotate and draw in upon closing so that the door is cinched tightly to the frame.